PROVK

iTrader: (14)

Why do nitro engine button heads have dimples in them?
Are they meant to face a certain why?

Roelof

So far I was told the number of dimpels is information of the combustion room (shape and volume). It is normally faced to the exhaust port but I do not believe it makes a change if it is fitted otherwise

lil-bump

iTrader: (89)

In some engines the dimple mark you see on the button face comes from the locating pin that aligns the sleeve to the crankcase. If you use haed shims you will also see the same dimple.


Pass you soon...

freestyles

iTrader: (14)

I beleive that lil-bump got it spot on